WO2009096146A1 - Welding inspection method and welding inspection apparatus - Google Patents

Abstract

Disclosed is a welding inspection method which does not require the inspector to be highly skilled, does not require waiting for the spot welded part to cool off, and with which the probe is not consumed or damaged. A probe temporarily mounted close to the welded part on the surface of a metal plate emits ultrasonic waves from an oblique direction with respect to the boundary surfaces between a plurality of metal plates. At this time, the probe is temporarily mounted at the position where the incident ultrasonic waves pass through the welded part at the boundary between the plurality of metal plates in an oblique direction with respect to the boundary surfaces. Also, a display processing means displays the intensity of the reflected ultrasonic waves. Alternatively, the display processing means displays the details of the detection result estimated based on the intensity of the reflected ultrasonic waves.

Description

Welding inspection method and welding inspection apparatus

The present invention relates to a welding inspection method and a welding inspection apparatus.

In the automobile assembly process, welding is frequently used. The reason is that a structural material obtained by joining the ends of thin steel plates and welding them is often used. For example, a truck frame is a thick steel plate bent into a U-shape. In this case, the cabin, the roof, and the like are made by combining bent thin steel plates to form a structural material having a square cross section. As described above, in the production of automobiles, a material obtained by welding a thin steel plate that has been pressed and bent is frequently used.

As a conventional welding inspection method related to the present invention, ultrasonic inspection will be described with reference to FIGS. FIG. 1 and FIG. 2 are diagrams for explaining a conventional welding inspection method, in which a conventional ultrasonic probe (hereinafter simply referred to as a probe) 10 and steel plates 13-1 and 13-2 as inspection materials are shown. It is a figure which shows these positional relationships. FIG. 3 is a view showing a welded portion (referred to as a nugget) 12. In the following description, spot welding will be described, but the application range of the present invention is not limited to spot welding.

The probe 10 includes a probe 11, and the probe 11 includes an ultrasonic transmission / reception element. The probe 11 is connected to a welding inspection apparatus (not shown), and transmits and receives ultrasonic waves as pulse signals. The welding inspection apparatus receives a reflected wave and measures its intensity every time one pulse signal is transmitted.

Further, the probe 10 includes a contact portion 14, and the inside of the contact portion 14 is filled with a liquid such as water. Thereby, the ultrasonic wave emitted from the probe 11 can be efficiently transmitted to the steel plate 13-1. Further, the contact portion 14 is formed of elastic rubber or the like so that the degree of adhesion between the probe 10 and the steel plate 13-1 does not change even if the angle of the probe 10 changes slightly.

As shown in FIG. 3, the nugget 12 is formed on the boundary surface between the superposed steel plates 13-1 and 13-2. FIG. 3 shows an example in which two steel plates 13-1 and 13-2 are overlapped, but the same applies even when the number of overlapped sheets is two or more.

As shown in FIG. 1 and FIG. 2, in the conventional ultrasonic welding inspection method, it is necessary to inspect with the probe 10 directly above the nugget 12, that is, directly above the spot welding site 15.

The reason is that the inspection is not established unless the ultrasonic wave emitted from the probe 10 passes through the nugget 12 and the reflected wave of the ultrasonic wave is not necessarily received. Therefore, the probe 10 is necessarily applied directly above the spot welding site 15. Furthermore, in order to obtain a reflected wave efficiently, the ultrasonic reflection surface must be substantially perpendicular to the traveling direction of the ultrasonic wave, and the angle adjustment of the probe 10 requires accuracy.

4 to 9 are diagrams for explaining a specific example of a conventional welding inspection method using ultrasonic waves. FIG. 5 is a diagram showing the test results for the normal nugget 12, where the horizontal axis represents time and the vertical axis represents reflected wave intensity.

The ultrasonic waves emitted from the probe 10 toward the steel plate 13-1 reciprocate several times between the surface of the steel plate 13-1 and the back surface of the steel plate 13-2 during a certain period of time. Energy decays and disappears. While this ultrasonic wave reciprocates in the steel plates 13-1 and 13-2, a part of the ultrasonic wave reflected between the surface of the steel plate 13-1 and the back surface of the steel plate 13-2 returns to the probe 10. FIG. 5 shows an example in which an image is displayed using an image display device (such as an oscilloscope) so that the examiner can visually recognize the waveform of the ultrasonic wave returned to the probe 10.

FIG. 5 shows an ultrasonic waveform when the state of the nugget 12 is normal. In this case, a plurality of repetitive waveforms depending on the thickness of the steel plates 13-1 and 13-2 appear, and a waveform pattern is output in which the repetitive waveforms draw a predetermined attenuation curve. The quality determination of the nugget 12 is performed by evaluating the number of these waveforms, the peak value of each waveform, the distance between each waveform, the presence or absence of a waveform that does not originally appear, and the like.

Note that the speed of propagation through the ultrasonic nugget 12 is constant. Accordingly, a plurality of reflected waves reflected on the back surface of the steel plate 13-2 appear at ultrasonic transmission time intervals corresponding to the plate thicknesses of the steel plates 13-1 and 13-2. Therefore, the horizontal axis is a time axis indicating the distance in the plate thickness direction of the steel plates 13-1 and 13-2 (see, for example, Patent Document 1).

On the other hand, FIG. 6 is a diagram showing a state in which the nugget 12 is not formed normally and peeling occurs between the steel plates 13-1 and 13-2. FIG. 7 is a diagram showing a test result for an incomplete nugget 12 in which peeling has occurred. Time is taken on the horizontal axis and the intensity of the reflected wave is taken on the vertical axis.

In the state where the nugget 12 is not formed normally and peeling occurs between the steel plates 13-1 and 13-2, as shown in FIG. 7, repeated reflected waves having a plate thickness on the flaw detection surface side with small attenuation appear. To do. That is, in a state where peeling occurs between the steel plates 13-1 and 13-2, the ultrasonic wave emitted from the probe 10 reciprocates only between the front surface and the back surface of the steel plate 13-1. Therefore, since the propagation distance of the ultrasonic wave is shorter than the example of FIG. 5, the distance between the waveforms is shorter than that of FIG. In addition, since the propagation distance of the ultrasonic wave is short, the amount of attenuation is smaller than that in FIG. 5, so that waveforms having the same intensity continue at short intervals. When such a waveform appears, it can be determined that there is peeling between the steel plates 13-1 and 13-2.

FIG. 8 is a diagram showing a state in which a small nugget 12 is formed. FIG. 9 is a diagram showing the test results for the small nugget 12, where the horizontal axis represents time and the vertical axis represents reflected wave intensity.

When the nugget 12 smaller than the normal case is formed, the normal nugget 12 shown in FIG. 5 is formed in the inspection range by the probe 10 and the peeling shown in FIG. 7 is generated. And the same state as appearing in parallel. Therefore, a waveform in which the large waveform shown in FIG. 5 and the small waveform shown in FIG. 7 are mixed appears. In particular, a small waveform that appears between large waveforms is called a Napoleon hat. When such a Napoleon hat appears, it can be determined that a smaller nugget 12 is formed than in a normal case.

As described above, conventionally, the probe 10 is placed on the nugget 12 at a right angle to the steel plate 13-1, and the inspection is performed.

JP 2006-153710 A JP 2006-71422 A JP 2007-232525 A JP 2007-232526 A

In the conventional welding inspection method, accurate measurement cannot be performed unless a probe is applied at a right angle to the steel plate immediately above the nugget, that is, immediately above the spot welding site. If this is performed manually by the inspector, there is a problem that it cannot be denied that the accuracy of the inspection varies depending on the skill level of the inspector.

Also, in order to apply the probe directly above the spot welded part, it is necessary to wait for the temperature of the spot welded part to drop, which causes a problem that inspection efficiency is lowered.

In general, the probe has a contact portion (reference numeral 14 in FIG. 1) formed of a material having elasticity such as rubber. And it is comprised so that the probe and a steel plate may be closely_contact | adhered by pressing this contact part on a steel plate. There is a problem that the contact portion is easily consumed or damaged by inspecting the contact portion formed of such a flexible material in close contact with the spot welding site.

The present invention has been made to solve such a problem, and does not require the skill level of the inspector, and does not need to wait for the temperature of the spot welded portion to decrease. It is an object of the present invention to provide a welding inspection method and a welding inspection apparatus in which a portion is not consumed or damaged.

When the present invention is viewed from a viewpoint as a welding inspection method, the present invention is a welding inspection method for judging the quality of welding performed on a plurality of stacked metal plates. The probe temporarily placed on the surface makes ultrasonic waves incident on the boundary surfaces of the plurality of metal plates from an oblique direction.

At this time, the probe is temporarily placed at a position where ultrasonic waves incident obliquely with respect to the boundary surface of the metal plate pass through the nuggets generated at the boundary of the plurality of metal plates.

Also, the display processing means can display an image of ultrasonic reflected waves. Alternatively, the display processing means can display the contents of the inspection result estimated based on the intensity of the reflected wave of the ultrasonic wave. Alternatively, the display processing unit can output information indicating the inspection result estimated based on the intensity of the reflected wave of the ultrasonic wave to the external device.

For example, welding is spot welding.

According to this, it is not necessary to apply a probe almost directly to the steel plate immediately above the nugget, that is, immediately above the spot welded portion, and an accurate inspection can be performed regardless of the skill level of the inspector.

Furthermore, since it is not necessary to apply a probe directly above the spot welded part, it is not necessary to wait for the temperature of the spot welded part to drop, and the inspection efficiency can be improved.

Furthermore, the probe does not have a contact portion formed of a flexible material such as rubber, so that the probe is not consumed or damaged.

Further, when the present invention is viewed from the viewpoint of a welding inspection apparatus, the present invention is a welding inspection apparatus for judging the quality of welding performed on a plurality of stacked metal sheets. It is characterized by comprising a probe that is temporarily placed in the vicinity of the part, and means for making ultrasonic waves incident on the boundary surfaces of the plurality of metal plates from an oblique direction through the probe.

Furthermore, a display processing means for displaying an image of reflected ultrasonic waves can be provided. Alternatively, display processing means for displaying the contents of the inspection result estimated based on the intensity of the reflected wave of the ultrasonic wave can be provided. Alternatively, a display processing unit that outputs information indicating an inspection result estimated based on the intensity of the reflected wave of the ultrasonic wave to an external device can be provided.

According to the present invention, an accurate inspection can be performed regardless of the skill level of the inspector. In addition, the probe is not consumed or damaged. Furthermore, it does not depend on the accuracy of the shape of the welded part. Thereby, inspection efficiency can be improved.

It is a figure for demonstrating the conventional welding inspection method. It is a figure for demonstrating the conventional welding inspection method. It is a figure which shows a nugget. It is a figure for demonstrating the specific example of the welding inspection method by the conventional ultrasonic wave (state in which the normal nugget was formed). It is a figure which shows the test result with respect to the conventional normal nugget. It is a figure for demonstrating the specific example of the welding inspection method by the conventional ultrasonic wave (The state where the nugget was not formed normally but peeling occurred between steel plates). It is a figure which shows the test result with respect to the incomplete nugget which the conventional peeling produced. It is a figure for demonstrating the specific example of the welding inspection method by the conventional ultrasonic wave (state in which the small nugget was formed). It is a figure which shows the test result with respect to the conventional small nugget. It is a block block diagram of the welding inspection apparatus of embodiment of this invention. It is a figure for demonstrating the welding inspection method of embodiment of this invention. It is a figure for demonstrating the welding inspection method of embodiment of this invention. It is a figure for demonstrating the specific example of the welding inspection method by the ultrasonic wave of embodiment of this invention (state in which the nugget was formed normally). It is a figure which shows the test result with respect to the normal nugget of embodiment of this invention. It is a figure for demonstrating the specific example of the welding test | inspection method by the ultrasonic wave of embodiment of this invention (The state where the nugget was not formed normally but peeling occurred between steel plates). It is a figure which shows the test result with respect to the incomplete nugget with which peeling of embodiment of this invention produced. It is a figure for demonstrating the specific example of the welding inspection method by the ultrasonic wave of embodiment of this invention (the state where the small nugget was formed). It is a figure which shows the test result with respect to the small nugget of embodiment of this invention. It is a flowchart which shows the process sequence of the display control part of embodiment of this invention. It is a figure (perspective view) for demonstrating a test | inspection auxiliary | assistance instrument. It is a figure (side view) for demonstrating a test | inspection auxiliary | assistance instrument. It is a figure for demonstrating the example in which the precision of the shape of a welding site | part deteriorates. It is a figure which shows the mode of the test | inspection in the welding site | part which is not a regulation shape by the welding test | inspection method of embodiment of this invention. It is a figure which shows the mode of the test | inspection in the welding site | part which is not a regulation shape by the conventional welding test | inspection method. It is a figure which shows a mode that it test | inspects from one position with respect to one spot welding location in the conventional welding inspection method. It is a figure which shows a mode that it test | inspects from several position with respect to one spot welding site | part. It is a figure which shows a mode that it test | inspects from several position with respect to one spot welding site | part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10 Probe 2, 11 Probe 3 Pulse oscillator 4 Receiver 5 Data analysis part 6 Display control part 7 Display part 8 Display processing part 9 External device 12 Nugget 13-1, 13-2 Steel plate 14 Contact part 15 Spot welding Site 16 End 17 Inspection aid 18-1, 18-2 Welding electrode

Embodiments of the present invention will be described with reference to FIGS. FIG. 10 is a block configuration diagram of the welding inspection apparatus according to the embodiment of the present invention. As shown in FIG. 10, the welding inspection apparatus according to the embodiment of the present invention includes a probe 1 that is temporarily placed in the vicinity of a welded portion on the surface of a steel plate 13-1, and steel plates 13-1 and 13 via the probe 1. -2 is provided with a probe 2 which is a means for making an ultrasonic wave incident on the boundary surface of -2.

Furthermore, a display processing unit 8 which is a display processing means for displaying an image of an ultrasonic reflected wave is provided. Or the display process part 8 which is a display process means which displays the content of the test result estimated based on the intensity | strength of the reflected wave of an ultrasonic wave is provided. Further, the display processing unit 8 can also output information such as “normal”, “with peeling”, and “small nugget” to the external device 9. The external device 9 is, for example, a test result recording device, a test result transfer device, a test result abnormality alarm device, or the like.

Hereinafter, spot welding will be described, but the application range of the embodiment of the present invention is not limited to spot welding.

The probe 2 includes an ultrasonic transmission / reception element (not shown). The pulse oscillator 3 gives a pulse signal as an electric signal to the ultrasonic transmitting / receiving element of the probe 2. An ultrasonic transmission / reception element to which a pulse signal as an electric signal is given generates an ultrasonic wave in accordance with the given pulse signal. The ultrasonic transmitting / receiving element receives a pulse signal as an ultrasonic reflected wave, converts the pulse signal into an electric signal, and outputs the electric signal to the receiver 4. The receiver 4 converts a pulse signal as a reflected wave of an ultrasonic wave input as an electric signal from the transmitting / receiving element of the probe 2 into a signal form that can be input by the data analysis unit 5 and outputs the signal form to the data analysis unit 5. .

The data analysis unit 5 receives the pulse signals from the receiver 4 and the pulse oscillator 3 and analyzes the time difference and the intensity difference of the pulse signals from both. Thereby, it is possible to analyze how the ultrasonic wave emitted from the probe 1 is reflected and attenuated in the steel plates 13-1 and 13-2.

The analysis result of the data analysis unit 5 is sent to the display control unit 6, and the display control unit 6 displays a waveform image that allows the inspector to visually check the analysis result, or “normal”, “with peeling”, “ It is displayed on the display unit 7 as character information such as “nugget small”. Alternatively, information such as “normal”, “with peeling”, “small nugget” is output to the external device 9. The external device 9 is, for example, a test result recording device, a test result transfer device, a test result abnormality alarm device, or the like.

FIG. 11 and FIG. 12 are diagrams for explaining the welding inspection method according to the embodiment of the present invention. The probe 1 according to the embodiment of the present invention and the steel plates 13-1 and 13-2 as inspection objects are shown in FIG. It is a figure which shows these positional relationships.

As shown in FIGS. 11 and 12, in the ultrasonic welding inspection method according to the embodiment of the present invention, it is not necessary to perform inspection by applying the probe 1 directly above the nugget 12, that is, directly above the spot welded portion 15. That is, the inspection can be performed by temporarily placing the probe 1 in the vicinity of the spot welded portion 15 in the steel plate 13-1.

That is, as shown in FIG. 11, the ultrasonic wave emitted from the probe 2 enters the steel plate 13-1 via the probe 1. The ultrasonic wave incident on the steel plate 13-1 does not enter the steel plate 13-2 side at the boundary surface where the steel plate 13-1 and the steel plate 13-2 are not coupled, and the steel plate 13-1 and the steel plate 13-2 are not connected. It passes through the bonded nugget 12 and enters the steel sheet 13-2. The ultrasonic wave incident on the steel plate 13-2 is reflected at the end 16 of the steel plate 13-2 and returns into the steel plate 13-2.

As described above, in the welding inspection method using ultrasonic waves according to the embodiment of the present invention, the state of the nugget 12 is known by detecting the ultrasonic waves reflected by the end portions 16 of the steel plates 13-1 and 13-2. Can do. Accordingly, as shown in FIG. 12, the position where the probe 1 is temporarily placed on the steel plate 13-1 inevitably has a nugget 12 (or spot welded portion 15) between the end 16 and the probe 1. Position. The direction of the probe 1 is a direction in which ultrasonic waves are emitted toward the nugget 12 (or the spot welded portion 15).

Also, as shown in FIG. 12B, the ultrasonic emission direction of the probe 1 (shown by a one-dot chain line) is set to be perpendicular to the surface of the end portion 16. Thereby, since the reflected wave at the end 16 of the ultrasonic wave emitted from the probe 1 efficiently returns in the direction of the probe 1, a highly accurate inspection can be performed.

As in the conventional example shown in FIGS. 1 and 2, in order to apply the probe 10 at right angles to the steel plate 13-1 immediately above the nugget 12 (or spot welded portion 15), the inspector However, it is necessary to hold the probe 10 at a right angle with respect to the steel plate 13-1 by hand during the inspection. At this time, the determination as to whether or not the probe 10 is perpendicular to the steel sheet 13-1 can be made only with a general sense of visual inspection by the inspector, and the skill level of the inspector is required.

On the other hand, in the embodiment of the present invention, as shown in FIG. 12B, the probe 1 is attached to the steel plate 13-1 so that the ultrasonic emission direction of the probe 1 is perpendicular to the surface of the end portion 16. Put it on top temporarily. At this time, the angle at which the probe 1 is temporarily placed on the surface of the end portion 16 can be easily confirmed by shaking the probe 1. Thereby, adjustment to the optimal position which can be carried temporarily can be performed easily. Therefore, the skill level of the inspector is not required. Moreover, the workability of the inspection work is better than that of the conventional example.

Further, by adjusting the angle α formed by the probe 2 and the steel plate 13-1 shown in FIG. 11, the angle of the probe 2 with respect to the plate thickness of the steel plates 13-1 and 13-2 is adjusted to an optimum angle. can do. That is, the incident angle of the ultrasonic wave emitted from the probe 1 with respect to the surface of the steel plate 13-1 can be adjusted by adjusting the angle α. Thereby, it is possible to cope with the inspection of the steel plates 13-1 and 13-2 having various plate thicknesses.

Also, it is desirable that the size of the probe 1 is approximately equal to or smaller than the diameter of the nugget 12 to be inspected. For example, when the size of the probe 1 is larger than the diameter of the nugget 12, ultrasonic waves are incident on the outside of the nugget 12, and a reflected wave (noise) unnecessary for inspection is generated.

Thus, according to the welding inspection method of the embodiment of the present invention, the conventional problem can be solved. That is, as described above, it is not necessary to apply the probe 1 at a right angle to the steel plate 13-1 immediately above the spot welding site 15. Therefore, highly accurate inspection can be performed regardless of the skill level of the inspector.

Also, it is not necessary to apply the probe 1 directly above the spot welding site 15. Therefore, there is no need to wait for the temperature of the spot welded portion 15 to drop. Accordingly, a decrease in inspection efficiency can be avoided.

Also, the wedge, which is the part where the probe 1 and the steel plate 13-1 are in direct contact, can be produced using a rigid material such as acrylic. For this reason, it is not consumed or damaged like the contact portion 14 of the conventional example.

13 to 18 are diagrams for explaining a specific example of the welding inspection method using ultrasonic waves according to the embodiment of the present invention. FIG. 13 is a diagram illustrating a state in which the nugget 12 is normally formed. FIG. 14 is a diagram showing the test results for the normal nugget 12, where the horizontal axis represents time and the vertical axis represents reflected wave intensity.

As shown in FIG. 13, the probe 1 is temporarily placed at the appropriate position as described above in the vicinity of the spot welding portion 15. Thereby, the ultrasonic wave incident on the inside of the steel plate 13-1 enters the inside of the steel plate 13-2 via the nugget 12. When the ultrasonic wave incident on the inside of the steel plate 13-2 is reflected at the end 16 of the steel plate 13-2, it is further reflected inside the steel plate 13-2, but hardly returns to the steel plate 13-1. Therefore, almost no reflected wave appears as shown in FIG.

Accordingly, as an inspection procedure, the probe 1 is temporarily placed at a position where the direction of ultrasonic wave emission is perpendicular to the end 16 and the spot welded portion 15 is between the end 16 and the probe 1. Is moved little by little to search for a position where the reflected wave has a predetermined minimum value.

Also, at this time, if the position where the reflected wave has a predetermined minimum value cannot be found, it can be determined that the welding is not properly performed as described below.

FIG. 15 is a diagram showing a state in which the nugget 12 is not normally formed and peeling occurs between the steel plates 13-1 and 13-2. FIG. 16 is a diagram showing a test result for an incomplete nugget 12 in which peeling has occurred. Time is taken on the horizontal axis and the intensity of the reflected wave is taken on the vertical axis.

As shown in FIG. 15, in the state where peeling occurs between the steel plates 13-1 and 13-2, the ultrasonic wave incident on the steel plate 13-1 from the probe 1 does not enter the steel plate 13-2. Reflected by the end 16 of the steel plate 13-1. Since this reflected wave is further reflected in the steel sheet 13-1, a strong reflected wave appears as shown in FIG.

FIG. 17 is a diagram showing a state in which a small nugget 12 is formed. FIG. 18 is a diagram showing the inspection results for the small nugget 12, where the horizontal axis represents time and the vertical axis represents reflected wave intensity.

As shown in FIG. 17, in the state where the small nugget 12 is formed, a part of the ultrasonic wave incident on the steel plate 13-1 from the probe 1 enters the steel plate 13-2 via the small nugget 12. However, the remaining ultrasonic waves are reflected by the end 16 of the steel plate 13-1. This reflected wave is repeatedly reflected in the steel plate 13-1. For this reason, as shown in FIG. 18, a reflected wave stronger than the case of the normal nugget 12 shown in FIG. 14 appears.

In this way, when the nugget 12 is formed normally, or when the nugget 12 is not formed normally and peeling occurs between the steel plates 13-1 and 13-2, or the nugget 12 is in conformity with the standard. It is possible to make a determination for each of the cases where the size is small.

In addition, as shown in FIGS. 14, 16, and 18, the display form on the display unit 7 is determined by displaying the waveform of the reflected wave itself and visually checking it. Alternatively, based on the reflected wave intensity analyzed by the data analysis unit 5, the display control unit 6 displays character information such as “normal”, “with peeling”, “small nugget”, and the like. Alternatively, information such as “normal”, “with peeling”, and “small nugget” may be output to the external device 9. Of course, the information can be output to the external device 9 while being displayed on the display unit 7. The output of information to the external device 9 can be used to automatically perform inspection recording, transfer inspection results to a plurality of locations, warn of abnormalities in inspection results, and the like.

FIG. 19 is a flowchart showing a processing procedure of the display control unit 6 in the latter case. That is, as shown in FIG. 19, the display control unit 6 monitors the reflected wave intensity analyzed by the data analysis unit 5 (step S1), and when the reflected wave intensity is smaller than a predetermined value (Yes in step S2). ) “Normal” is displayed on the display unit 7 and / or information “Normal” is output to the external device 9 (step S5). If the reflected wave intensity is not smaller than the predetermined value (No in step S2), but not larger than the predetermined value (No in step S3), “small nugget” is displayed on the display 7 and / or on the external device 9 On the other hand, the information “small nugget” is output (step S4). If the reflected wave intensity is greater than the predetermined value (Yes in step S3), the display unit 7 displays "Peeling off" and / or outputs information "Peeling off" to the external device 9. (Step S6).

(Examples of inspection aids)
An embodiment of the inspection aid will be described with reference to FIGS. 20 and 21. FIG. FIG. 20 and FIG. 21 are diagrams for explaining an example of the inspection assisting instrument 17. 20 is a perspective view, and FIG. 21 is a side view. As shown in FIG. 20, spot welding is often performed continuously on the steel sheet 13-1. In such a case, the distance between the end portion 16 and the spot welded portion 15 is substantially constant. Therefore, once the distance of the probe 1 from the end portion 16 is determined, the probe 1 is slid in the longitudinal direction of the steel plates 13-1 and 13-2 as it is. Thereby, the spot welded part 15 can be continuously inspected.

That is, as shown in FIGS. 20 and 21, the tip portion of the inspection auxiliary instrument 17 bent at a right angle is applied to the end portion 16. Thereby, the distance between the end 16 and the probe 1 can be kept constant. In this way, it is possible to continuously inspect the spot welded portion 15 provided continuously on the steel plate 13-1.

Although not shown, the inspection auxiliary instrument 17 is provided with a mechanism that can adjust the position of the probe 1 on the inspection auxiliary instrument 17. Then, the tip portion of the inspection auxiliary instrument 17 bent at a right angle is applied to the end portion 16 to adjust the optimum position with respect to one spot welded portion 15. If the optimum position can be adjusted in this way, thereafter, the inspection auxiliary instrument 17 is slid on the steel plates 13-1 and 13-2. Thereby, the optimal position of the probe 1 can be obtained with respect to the other spot welding sites 15. Thus, the inspection efficiency can be dramatically increased by using the inspection auxiliary instrument 17.

(Explanation of effect)
According to the welding inspection method of the embodiment of the present invention, as described above, the conventional problems can be solved. In addition, there is an effect that the inspection can be performed without depending on the accuracy of the shape of the welded part. This effect will be described with reference to FIGS.

An example in which the accuracy of the shape of the welded portion is degraded will be described with reference to FIG. FIG. 22 is a diagram for explaining an example in which the accuracy of the shape of the welded portion deteriorates. For example, as shown in FIG. 22A, when the steel plate 13-1 is a thin plate and the steel plate 13-2 is a thick plate, as shown in FIG. 22B, the welding electrode 18-1 And 18-2 are in contact with the steel plates 13-1 and 13-2 at a slight angle. In such a case, as shown in FIG. 22 (c), warpage may occur in the thin steel plate 13-1 after welding due to the stress caused by the pressurization of the welding electrodes 18-1 and 18-2. In this way, the shape of the welded portion where the nugget 12 is present may not be the prescribed shape.

FIG. 23 is a diagram illustrating a state of inspection with a welded part shape that is not a prescribed shape by the welding inspection method according to the embodiment of the present invention. Moreover, FIG. 24 is a figure which shows the mode of the test | inspection in the welding site | part which is not a regular shape by the conventional welding test | inspection method. As shown in FIG. 23, according to the welding inspection method of the embodiment of the present invention, the ultrasonic wave incident on the steel plate 13-1 enters the steel plate 13-2 via the nugget 12, and is reflected by the end portion 16. If it can be done, there will be no trouble in executing the inspection.

On the other hand, as shown in FIG. 24, in the conventional welding inspection method, it is indispensable to receive the reflected wave from the bottom of the steel plate 13-2. For this reason, when the reflection surface of the ultrasonic wave is not perpendicular to the incident direction of the ultrasonic wave, the reflected wave is reflected in a direction other than the probe 10 and it is difficult to perform a high-precision inspection.

As described above, according to the welding inspection method of the embodiment of the present invention, it is possible to inspect the steel plates 13-1 and 13-2 having a welded portion which is not a prescribed shape.

FIG. 25 is a view showing a state in which one spot welding site 15 is inspected from one position in the conventional welding inspection method. As shown in FIG. 25, conventionally, since it is necessary to apply the probe 10 at a right angle to the steel plate surface having the spot welded portion 15, it is not possible to inspect one spot welded portion 15 from a plurality of positions. could not.

On the other hand, according to the welding inspection method of the embodiment of the present invention, one spot welding site 15 can be inspected from a plurality of positions. FIG. 26 and FIG. 27 are diagrams showing a state in which inspection is performed on a single spot welded portion 15 from a plurality of positions. Thus, in the welding inspection method according to the embodiment of the present invention, it is possible to inspect one spot welded portion 15 from the position shown in FIG. 26 and the position shown in FIG. That is, the inspection can be performed if there is a spot welding portion 15 between the probe 1 and the end portion 16 and the ultrasonic wave emitted from the probe 1 is reflected by the end portion 16. For example, even when the steel plate is bent, if the propagation of the ultrasonic wave is not hindered by the bent portion, it is possible to inspect the welded portion existing ahead of the bent portion from the front of the bent portion.

Furthermore, as described above, since it is possible to inspect even a welded portion that is not in a prescribed shape, it is possible to relax restrictions on selection of the inspection position. Thereby, compared with the past, inspection accuracy can be made high.

According to the present invention, an accurate inspection can be performed regardless of the skill level of the inspector. In addition, the probe is not consumed or damaged. Furthermore, it does not depend on the accuracy of the shape of the welded part. Accordingly, there is a possibility that the present invention can be applied to the development of an apparatus for automatically inspecting welding on a production line.

Claims (10)

In a welding inspection method for judging the quality of welding performed on a plurality of stacked metal plates,
A welding inspection method, wherein a probe temporarily placed in the vicinity of a welded portion on the surface of the metal plate causes ultrasonic waves to be incident on the boundary surfaces of the plurality of metal plates from an oblique direction. The welding inspection method according to claim 1,
Temporarily placing the probe on a position where ultrasonic waves incident from an oblique direction with respect to the boundary surface pass through the welded portion formed on the boundary surface of the plurality of metal plates;
A welding inspection method characterized by that. In the welding inspection method according to claim 1 or 2,
Display processing means displays an image of the reflected ultrasonic wave;
A welding inspection method characterized by that. In the welding inspection method according to claim 1 or 2,
The display processing means displays the contents of the test result estimated based on the intensity of the reflected wave of the ultrasonic wave.
A welding inspection method characterized by that. In the welding inspection method according to claim 1 or 2,
The display processing means outputs information indicating the test result estimated based on the intensity of the reflected wave of the ultrasonic wave to the external device.
A welding inspection method characterized by that. In the welding inspection method according to any one of claims 1 to 5,
The welding is spot welding,
A welding inspection method characterized by that. In a welding inspection apparatus for judging the quality of welding performed on a plurality of stacked metal plates,
A probe that is temporarily placed in the vicinity of the welded portion of the metal plate surface;
Means for causing ultrasonic waves to enter from an oblique direction with respect to the boundary surfaces of the plurality of metal plates through the probe;
A welding inspection apparatus comprising: The welding inspection apparatus according to claim 7,
Comprising display processing means for displaying an image of an ultrasonic reflected wave;
A welding inspection apparatus characterized by that. The welding inspection apparatus according to claim 7,
Comprising display processing means for displaying the content of the test result estimated based on the intensity of the reflected wave of the ultrasonic wave,
A welding inspection apparatus characterized by that. The welding inspection apparatus according to claim 7,
Comprising display processing means for outputting information indicating an inspection result estimated based on the intensity of the reflected wave of the ultrasonic wave to an external device;
A welding inspection apparatus characterized by that.

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